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BACKGROUND:Lipopexia induced by glucocorticoid is fat precipitation in marrow due to abnormal lipomatabolism,or differentiation of cells resulting from hormone-affected bone marrow mesenchymal cells.The precise generating procedure remains unclear.OBJECTIVE:To Jnvastigate effects of vadous concentrations of dexamethasone on adipogenic differentiation of bone marrow mesenchymal cells.DESIGN,TIME AND SETTING:The observational study was performed at the Department of Biochemistry,China Medical University from January 2007 to January 2009.MATERIALS:A total of 80 Sprague-Dawley rats aged 3 or 4 weeks,weighing (110±10) g,of both genders,were used in this study.METHODS:Rat bone marrow mesenchymal cells were isolated and subcultured.Bone marrow masenchymal cells at the third passage were used as samples.MAIN OUTCOME MEASURES:Cellular morphologic changes after treatment of 10~(-7) mol/L dexamethasone were observed under an inverted microscope,as well as at 3,7,14 and 21 days under normal culture condition.Morphological changes of bone marrow mesenchymal cells were observed following alkaline phosphatase and Sudan Ⅲ staining.Alkaline phosphatase activity was measured using phenol reagent.Effects of dexamethasone on cell proliferation were measured using MTT assay.RESULTS:Following 24 hours of incubation,a few adherent cells were found in the bottom of the culture flask,showing spindle shape.With prolonged time,adherent cells became more,presenting radiated shape.Following passage,cells distributed uniformly,showing typical fibroblast-shape.Following dexamethasone stimulation,cells changed from spindle-shape into polygonal or irregular shape.In the late phase,with increased concentration and prolonged time,cell colonies disappeared;cells adhered,and died.In normal cultured cells,no or a few orange particles were found.In dexamethasone-cultured cells,with increased hormone concentration and prolonged time,Sundan Ⅲ stained particles increased.At 21 days,alkaline phosphatase activity under normal culture was separately 1.57-,4.49-and 5.0-fold of 10~(-8),10~(-7),10~(-6) mol/L dexamethasone group.At 7,14 and 21 days,alkaline phosphatase activity under normal culture was separately 2.93-,3.80-and 4.39-fold of 10~(-7) mol/L dexamethasone group (P ＜ 0.05).High concentration of dexamethasone had significant inhibitory effects on cell proliferation activity.Significant difference was detected as compared 10~(-7) mol/L and 10~(-6) mol/L to other groups (P ＜ 0.05).CONCLUSION:High-dose dexamethasone enhances adipogenic and suppresses osteoblastic differentiation of bone marrow mesenchymal cells.The effect will increase along with the increasing content and prolonged duration of demamethasone stimulation.
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BACKGROUND: Injectable hydrogel-chitosan is the latest developed material for cartilage tissue engineering. It provides a novel cell attachment mechanism. OBJECTIVE: To investigate the effect of allologous chondrocytes in combination with chitosan in repairing cartilage defects. DESIGN, TIME AND SETTING: Randomized controlled animal trial was performed at the Central Laboratory of China Medical University from November 2004 to March 2006. MATERIALS: Thirty 2-week-old New Zealand rabbits weighing 0.3 kg were selected to model cartilage defect. METHODS: Thirty rabbits were randomly divided into three groups. In the experimental group, the defects were repaired by the injection of second passage of chondrocytes (2.5?1011 L-1) combined with chitosan into articular capsule; the cell suspension group was only injected with chondrocyte suspension (2.5?1011 L-1); the control group was not given any treatment. MAIN OUTCOME MEASURES: The animals were sacrificed at the 4th, 8th, and 12th weeks after operation, respectively to harvest the lateral condyle of knee joint. Hematine-eosine staining, gross and histological examinations, and electron microscopic evaluations were performed to observe the repair condition. RESULTS: The gross observation showed that there was no obvious swelling or other inflammatory responses in each rabbits. Histological examination suggested that in the experimental group, the cartilage defects were repaired by the hyaline cartilage tissue with smooth surface, which integrated smoothly with articular cartilage at 12 weeks after operation. No obvious defect repair was observed in the other groups. The transmission electron microscopic observation showed that in the new-formation tissues of the experimental group, there were round or oval chondrocytes, and abundant rough endoplasmic reticulum, ribosome and Golgi complex in cytoplasm. At 8 to 12 weeks, plenty of collagen fibers were found in cell suspension group. In the control group, only fibrous tissues were seen on the surface of defects. CONCLUSION: The articular cartilage defects of rabbits are repaired with allograft of chondrocytes seeded onto chitosan, indicating chitosan can serve as carrier in cell transplantation.
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Objective To study the clinical characters and the prognosis of the sciatic nerve injury associated with acetabular fracture. Methods From January 1980 to January 2000, fourteen sciatic nerve injury resulted from acetabular fracture were observed. Three were treated with skeletal traction, eleven were treated with open reduction and internal fixation and neurolysis. Results All cases were followed-up for an average of 18 months. The anatomical reduction of acetabular fracture obtained in 57.1％ of the patients and satisfactory reduction in 42.9％ . The excellent and good nerve functional recovery was seen in 57.1％ according to MCRR. Conclusion Injury of the sciatic nerve associated with the acetabular fracture occurs most commonly when the hip is dislocated posteriorly. Injury of the common peroneal nerve, branching off from the sciatic nerve was more common and had poorer prognosis than that of the tibial nerve. Flexion of the knee and extension of the hip during the surgical reduction of acetabular fracture can reduce iatrogenic injury of the sciatic nerve. Early reduction of acetabular fracture and neurolysis is important for the recovery of function of the sciatic never.
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Objective To explore the capsular changes at the weight- bearing area of hip with osteoarthritis and its correlation to postoperative clinical results of Chiari pelvic osteotomy. Methods According to the Bombelli radiological classification, the 66 hips with osteoarthritis were classified into three groups: hypertrophic, normotrophic and atrophic. Specimens of the capsule at weight- bearing area were obtained during total hip replacement for osteoarthritis, and stained with HE, Van- Gieson and Safranin O. Histopathological changes of the capsules were observed and compared among the three groups. Results The hypertrophic group showed a high incidence of metaplastic cartilage (63.3％ ). Normotrophic group(32.1％ )and atrophic group(25.0％ ) showed a low incidence of metaplastic cartilage. The atrophic group had a higher incidence of fibrous synovitis or fibrosis(81.3％ ) than hypertrophic. Among the three group, the frequency of infiltration granulation tissues was low, the frequency of both infiltration of inflammatory cells and degeneration of collagen fiber was high. Conclusion Associating with clinical research, these findings suggest that the capsular changes at weight- bearing area are responsible for postoperative clinical results of Chiari pelvic osteotomy. Compared with normotrophic and atrophic type, the hypertrophic type has the best adaptation of Chiari pelvic osteotomy.
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Objective To explore the influence of abnormal mechanical stress on acetabular development, especially on the chondrocyte proliferation in acetabular growth plate, and to research the methods of the repair of acetabular dysplasia. Methods 60 Wistar rats of 3 weeks old were divided into three groups, and each group had twenty rats. The left side was experimental side, and the right side was control. In group A, the hip joint was dislocated by manipulation repeatedly within two weeks; in group B, the model of acetabular dysplasia was created by keeping the knee joint in extension through steel needle fixation. The needle was removed after two weeks of fixation; and in group C, the knee joint was fixed in continuous extension with steel needle. When at 5, 7, 9 and 12 weeks old, the rat acetabulum was observed through the soft X-ray photograph, histological method and electronic micrograph respectively. Results In group A, when the rat was 5 weeks old, the acetabular angle was larger roughly 5? than the control side. Malalignment of chondrocyte column in proliferative zone was observed. No difference was seen between the two sides at 7, 9 and 12 weeks old. In group B, when the rats was 5 weeks old, the acetabular angle increased compared to the control side. When the rat was 7 weeks old, malalignment of the chondrocyte column in proliferative and hypertrophic zone increased. When at 9 and 12 weeks old, histological changes became indistinct gradually. In group C, the acetabular angle kept increasing to the control side. The acetabular dysplasia became obvious and had no improving tendency. When the rat was 12 weeks old, the acetabular edge became adducting and flat. There was no obvious alignment of chondrocyte column. The nucleus of acetabular chondrocyte of the proliferative zone became smaller, endoplasmic reticulum and mitochondria decreased, and bubbles formed. Conclusion Acetabular dysplasia could recover when abnormal mechanical stress was released, and the congruence of the head and acetabulum were corrected in the highly growing period of acetabulum. The crucial reason to acetabular dysplasia is the metabolic changes of chondrocytes in proliferative zone of growth plate, which leads to tardy ossification of the acetabulum.